Why do men and women have and then act surprised and angry when they get pregnant or get an STD?

Hi everybody! I'm curious about something. Why do men and women have and I mean, in our US society, is heavily advertised and promoted yet no one likes the consequences when they unexpectedly occur. Do you think the urge to have is just nature and is simply uncontrollable? I think people always have a choice to do something or to not do something. Why don't people face up to bad ual decisions they've made in their life? I just don't understand it. It seems that men and women view as only a pleasurable act for each other with no regard to the possible consequences. Men and women also don't realize that no birth control is 100% effective. A female friend of mine had a one night stand last year while on the Depo-Shot but it failed. From that one night act, she got genital and she also now has a 3 month old daughter. She also can't find the father anywhere to collect child support mostly because she said to me she doesn't even remember his first name. To me, people are just stupid. Any answers would be appreciated. Thanks!